Searching problem !

Hi , i have customize function for search text. in controller


def search

    if (query = params[:q] )
          @postjob = Postjob.find(:all, :conditions => ["company_name =
?", query])


I can search text and i am getting desired result .Now main thing is
that when i search for blank text box i want to show message <h4>No
Match Found ! Try with different keywords.....</h4> or if i enter wrong
key work and search result comes nothing i want to print message no data
found ........
i tried lot with different conditions but i am not getting proper result

@postjob will never be nil. find :all, always returns an array (which
may or may not be empty)